1. Field of the Invention
The invention relates to a system for automatically dispensing beverages. More particularly, the invention relates to a system for automatically dispensing the ingredients of alcoholic mixed drinks according to pre-programmed recipes with minimal user input.
2. Description of the Related Art
The problems associated with manual preparation of alcoholic mixed drinks are well documented. These problems include, but are not limited to, accuracy, consistency and speed. A more thorough description of these and other issues related to manual drink preparation and proposed solutions appear in U.S. Pat. Nos. 3,940,019 and 3,991,911.
The above cited prior art patents also address problems peculiar to the large volumes involved in their use in a commercial environment. Those problems include re-supply, spillage, pilferage and accounting. To facilitate re-supply and minimize spillage, the prior art utilized ingredients in their original containers. The prior art also dealt with pilferage and accounting by including elaborate electro-mechanical means to track the use of ingredients. Prior art also included means to calculate and display the price to charge for a particular drink based upon its ingredients.
In the prior art, the means by which liquids are dispensed from their containers vary widely. In U.S. Pat. No. 3,940,019, a piston pump delivers a fixed amount of liquid with each stroke. The amount dispensed depends on the number of strokes directed by the control means. In U.S. Pat. No. 3,991,911, the arrangement of the apparatus ensures that the level in the reservoir remains constant. Upon actuation by the control means, compressed air forces liquid out of the reservoir.
While these means are quite different mechanically, their underlying operation is identical. Each dispenses liquid from its original container at a fixed flow rate. Once the means to dispense liquid at a fixed flow rate is established, the amount of liquid dispensed depends only on the time that the dispenser is activated. Furthermore, the time required to dispense a given amount of liquid (for example, an ounce) is always the same. Given a fixed rate of dispensation, the prior art dispensed different amounts of liquid (as required by different mixed drink recipes) by activating the dispensation means for different amounts of time.
In a fixed flow rate system, the accuracy and consistency of the amount of liquid dispensed depends solely on the apparatus"" timing capabilities. Prior art achieved extremely high timing reliability through the use of discrete electronic circuitry available at the time of invention.
While discrete electronic components provide repeatable performance, their operational flexibility is limited by the fact that they are interconnected by a fixed network of wiring. In the prior art, each mixed drink recipe consisted of a network of electronic components to actuate the dispensation means of each ingredient and associated timing circuits to control the duration and hence the amount of each ingredient dispensed.
In the prior art, a fixed number of mixed drinks was selectable by the user through an array of pushbuttons. Each pushbutton corresponded to a particular mixed drink and was wired to that particular mixed drink""s network of electronic components. Some examples of the prior art allowed for changing the performance of the recipe networks by mechanically adjusting resistors or capacitors or the movement of jumper wires. In essence, the apparatus described is an analog computer which was xe2x80x9cstate of the artxe2x80x9d at the time of invention.
Additional related art are U.S. Pat. Nos. 1,979,323; 3,097,670; 3,341,078; 3,675,820; 3,920,149; 4,282,987; 4,360,128; 4,493,441; 4,932,461; and European Patent Application EP 0 947 518 A1.
To assist in understanding the unique nature of the present invention described below, the basic characteristics of liquid flow out of a container and their impact on prior art will be reviewed. As stated previously, the high volumes of use in a commercial application necessitated dispensing liquids from their original containers. Liquor bottles (and other original containers) are not designed to dispense their contents in a uniform manner. Liquid flow rate is variable and depends on the amount of liquid remaining in the container. As described previously, prior art utilizes ingenious, yet complex, mechanical means to ensure that the flow rate is fixed and independent of the amount of contents remaining.
Considering a simple example of a container with some level of liquid and a hole in its bottom, barring any outside forces other than gravity, fluid mechanics predicts that the flow rate out of the hole at the bottom of the container is inversely proportional to the square root of the level in the container. As liquid is dispensed and the level in the container diminishes, the flow rate diminishes as well.
In a gravity flow system, the time required to dispense a given amount of liquid (for example, an ounce) is not constant but depends on the level in the container. In actuality, the time required to dispense the same amount increases as the level in the container decreases. If the control means actuates the dispensation means for a fixed period each time, less fluid will be delivered each time as the liquid level in the container diminishes. This is obviously undesirable from the standpoints of both accuracy and consistency.
Therefore a control system that depends on fixed flow rates and fixed dispensation times (as in prior art) is not compatible with a gravity flow system. The control means described in U.S. Pat. Nos 3,940,019 and 3,991,911 is linear in nature and worked well with fixed flow rates. It may be inferred that due to its non-linear nature, gravity flow was avoided because the control means available was not compatible. The limited control means was compensated for by mechanical dispensation means as previously described. Advances in Large Scale Integrated Circuits have progressed such that controlling external hardware and performing complex mathematical computations can be accomplished by a single chip computer.
It is an object of the present invention to provide a drink mixing and dispensing apparatus that does not depend on fixed flow rates.
In accordance with the present invention there is provided an automatic mixed drink dispensing apparatus wherein individual ingredients are combined according to pre-programmed recipes to produce a complete mixed drink. A digital computer provides the control means to interact with the user, store recipes and calculate dispensation times. The computer calculates dispensation times based upon the relationship between gravity flow and liquid level in the ingredient containers. The control system is physically isolated from the dispensation means and operates by electromagnetic repulsion.